Method of making pipes for electrical conduits.



it T l ll Cl NELSON H. RAYMOND, oE BUFFALO, NEW YORK, AssIeNoE To cLIEToN MANUEL/AC- TUBING COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF NEW JERSEY;

METHOD OF MAKING PIPES FOR ELECTRICAL CONDUITS;

No Drawing.

To all whom it may concern:

Be it known that I, NELSON H. RAYMOND, a citizen of the United States, residing at Buffalo, in the county of Erie, State of New York, have invented an Improvement in Methods of Making Pipes for Electrical Conduits, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention relates to metallic pipes for use in electrical conduits.

The qualifications of such pipes as prescribed by underwriters, must be strictly adhered to and by methods heretofore practised it has been very diflicult to secure a uniform product of the required high standard. Perhaps the most substantial difficulty has been encountered heretofore in rem0ving the different species of scale and the like, preparatory to applying a protective coating thereto, this removal of scale being particularly insisted upon by the aforementioned underwriters regulations. paring, for instance, iron pipes for electrical conduits, it is commonly attempted to remove therefrom three species of deleterious material, the ordinary mill scale, the oXid of iron, and the silica slag. It has been attempted to remove these by chemical treatment, dissolving one or more of the materials in an acid bath, and also by sandblasting either additionally to, or instead of, the chemical treatment. None of these methods has been capable of a substantially uniform product, since upon inspection much of the product was necessarily rejected, because of the presence of deleterious materials which should have been removed.

It is an object of the present invention to supply a method capable of producing a pipe which shall sustain such exacting requirements and rigid testsas it may be subjected to.

The character of the invention may be best understood by reference to an illustrative method embodying the invention, which is about to be described.

In order to remove the mill scale and silica slag, it is preferred to subject the untreated pipe to a thorough distorting or agitating action, which may be well exemplified by the action of a rapidly reciprocating or other hammer which, by its repeated impacts directed against the exterior Specification of Letters Patent.

Application filed January 30, 1909.

In pre- I Patented June 22, 1915. Serial No. 475,536.

of the pipe serves to give the same a temporary distortion and thorough agitation which loosens the scale and slag and jars it from its ordinary firm association with the pipe. Bythis means the pipe may be substantially cleared of scale and slag, but mere distortion or agitation does not ordinarily sufiice to disturb materially the oXid of iron which is more intimately incorporated with the body of the pipe. It is preferred to remove the oxid by an abrading action as, for instance, by means of a sand lap which may be inserted in the pipe and supplied with sand either dry or wet, as preferred. The interior of the pipe may be abraded by tumbling either in dry or wet sand, as desired. When the pipe has been so prepared by distorting or agitating it to remove the scale, and by abrading it to remove the iron oXid, both its inner and outer surfaces are substantially clean of deleterious material. It is then preferably supplied with a protective coating; and this may be done by galvanizing it or enameling it with any practicable substance applied in any practicable manner as by immersing the pipe in a bath of enamel. The pipe so treated when dried and in completed condition will sustain any of the rigid tests to which it may be subjected and the effective union between the protective coating and the previously prepared surface of the pipe retains the former in intimate association with the pipe and will preserve it substantially indefinitely.

As will appear to those skilled in the art the product of such a method as has been described above for illustration is very superior. It is devoid of any traces of acid such as were frequently found to remain in products of those processes employing chemical treatment for removal of deleterious material. The product is substantially purified of scale, slag, oXid of iron and other undesirable substances; and the substantially pure iron pipe is well coated by a protective covering.

One of the most substantial advantages of the above described method is its decided economy.

It is to be understood that the present in vention is not limited to the specific steps, and sequence of operations hereinbefore described for illustration. On the contrar as will appear to those skilled in the art,

the invention may be otherwise practised. It is not indispensable that all the features of the invention be used conjointly, since they may be used to advantage separately.

I claim.

1. An improvement in the art of making pipes for electrical conduits characterized by agitating, loosening and freeing the scale and slag therefrom by distortion and then abrading the same to remove the iron oxid and other deleterious materials.

2. An improvement in the art of making pipes for electrical conduits characterized by hammering to loosen and detach scale and slag therefrom and then abrading the 15 pipe by a sand lap to remove iron oxid and other deleterious materials.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing Witnesses.

NELSON H. RAYMOND.

WVitnesses LAURENCE A. JANNEY, EVERETT S. EMERY.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, .D. C. 

